China on Sunday started investigating complaints that American chicken products are being dumped in China and are unfairly benefiting from subsidies, adding to a string of trade disputes with Washington.

The Commerce Ministry said the probe was launched Sunday on broiler products and chicken products, following requests by Chinese companies to investigate the U.S. imports they say are hurting the domestic industry.

The investigation comes at a time of mutual finger pointing Washington and Beijing accusing the other of protectionism, which both say will hurt efforts to end the global economic crisis.

A U.S. labor union and three paper companies announced last week they had filed a new trade complaint over imports of Chinese paper. The move came a week after Beijing filed a World Trade Organization challenge to Washington's decision to raise tariffs on imports of Chinese-made tires.

The two governments also are involved in disputes over access to each others' markets for steel pipes, music and movies. On Tuesday, China appealed against a U.S. victory in a trade dispute over restrictions on the sale of U.S. music, films and books in the Chinese market.